Adjustable control switching mechanism

ABSTRACT

An adjustable control switching mechanism for machines having a repetitive cycle of operation, comprising a support fixed with respect to the machine, a part mounted for movement on the support and coupled to a shifting machine element to be moved correspondingly to such element, and a plurality of switch modules each having a micro-switch selectively shiftable therealong for actuation by the movable part as it is moved in response to the operation of the machine, with each microswitch connected to a machine function to actuate the machine in a predetermined cycle of operation.

ted States Patent Tenniswood et a1. Sept. 4, 1973 [541 ADJUSTABLECONTROL SWITCHING 3,192,350 6/1965 Horberg 200 47 x MECHANISM 2,650,2758/1953 Doutt 200 47 x 3,586,805 6/197] Ziegler 200/38 E Inventors: DavidM. Tenniswood, Troy; John E.

Arnold, Auburn Heights; Robert E. Kaptur, Birmingham; Toncho G. Tonchev,Detroit; Herbert J. Franke, Troy, all of Mich.

Assignee: Gemco Electric Company, Clawson,

Mich.

Filed: Jan. 6, 1972 Appl. No.: 215,826

U.S. Cl. 307/139, 200/47 Int. Cl. H0lh 3/16 Field of Search 307/139;200/47,

References Cited UNITED STATES PATENTS 6/1951 Loewenstein 200/38 EPrimary Examiner-Robert K. Schaefer Assistant Examiner-M. GinsburgAttorneyBurton & Parker [57] ABSTRACT An adjustable control switchingmechanism for machines having a repetitive cycle of operation,comprising a support fixed with respect to the machine, a part mountedfor movement on the support and coupled to a shifting machine element tobe moved correspondingly to such element, and a plurality of switchmodules each having a micro-switch selectively shiftable therealong foractuation by the movable part as it is moved in response to theoperation of the machine, with each microswitch connected to a machinefunction toactuate the machine in a predetermined cycle of operation.

15 Claims, 12 Drawing Figures PAIENTED ir 1 1 SHEET 1 OF 6 O O O O O O OO O O O PATENTED 4W3 SHEET 6 BF 6 ADJUSTABLE CONTROL SWITCHING MECHANISMBACKGROUND OF THE INVENTION 1. Field of the Invention The inventionpertains generally to the field of machine control, and moreparticularly to mechanism for controlling the operations of a machinehaving a repetitive operating cycle wherein a machine element shifts ina predetermined path during each cycle, the control mechanism beingoperably coupled to the element for linear correlated movement therewithto thereby sequentially actuate a plurality of switch means which areconnected to the machine to initiate the machine functions in timedsequence.

2. Description of the Prior Art In the art of machine control, it haslong been the practice to provide a plurality of limit switchesstrategically positioned for actuation by a movable part on the machineto thereby initiate and/or interrupt various machine functions. Forexample, in machines such as injection molding machines, initiation ofthe various machine functions is controlled by limit switches havingprojecting rollers, the switches being adjustably mounted on bars. Oneor more switch actuating rods are mounted on the machine for movementwith the machine element, the rods positioned adjacent the switches sothat as the rods are shifted in response to machine operation, theswitch rollers are contacted, thereby opening or closing the switchcontacts.

Very often it is necessary to vary the timing of the machine functions,and to this end, the limit switches above mentioned are usually clampedto their supporting bars, the clamps being manually releasable to permitadjustment of the switches along the bars. Using the injection moldingmachine again as an example, when different parts are to be molded onthe same machine, it is frequently necessary to change the timing ofvarious functions to properly mold each part. In order to accomplishthis, the limit switch clamps are loosened, and the switches arerepositioned along the bars.

As the machine timing must be quite accurate, it is frequently necessaryfor the operator to adjust the limit switches approximately, then cyclethe machine to visually observe the timing sequence, and then repeat theprocedure until the machine is operating in exactly the proper sequencefor the particular mold being used. This requires an experiencedoperator intimately familiar with the machine and the molds, and evenwith trained personnel, the change-over is laborious because of thetrial and error method that must be employed. In many cases it take theoperator up to ninety minutes or more to readjust the controls. This isunproductive down time for the machine, and obviously is undesirable.

Even apart from the length of time required to reset the machinecontrols, there is an ever-present danger to the operator if he attemptsto adjust the limit switches while the machine is in motion, which isnearly always the case. In a molding machine, the clamp speeds may beupwards of 100 feet per minute, with the switch-actuating rod or probemoving at the same speed. If the operator gets his hand, arm or a partof his clothing caught between the moving probe and a switch or switchbar, a serious injury could well result, and many such injuries have infact occured.

The instant invention overcomes these deficiencies of the prior art byproviding a compact control switching mechanism which can beconveniently mounted on existing machines and incorporated in the designof new machines, which mechanism is accessible for quick adjustment ofthe switches for controlling machine function without danger to themachine operator. Maximum versatility is assured by the provision of amechanism having virtually any desired number of individually adjustableswitch means in a single unit, depending upon the requirements of theparticular machine to be controlled. The same basic mechanism may beutilized to control different machines having a wide variety ofoperating characteristics. The basic adjustable switch module isconstructed so as to be adaptable to virtually all known machinesrequiring this type of control, and the mechanism may be adapted to anyparticular machine by merely providing different controlto-machine drivemeans adapted to the particular machine.

SUMMARY OF THE INVENTION The invention is directed to mechanism forcontrolling a machine having a repetitive cycle of operation, includinga part coupled to a movable machine element for movement in a linearpath correlated to the movement of the machine element, a plurality ofswitch means supported adjacent the moving part for actuation therebyduring movement of the part, each switch means being adjustablypositionable along said linear path to permit selective variation ofswitch actuation with respect to the cycle of machine operation. Alsocontemplated by the invention is a switch module having an elongatesupport upon which is guidably mounted a switch carriage, with switchmeans on the carriage, and means for selectively positioning thecarriage and switch at any desired position along the support.

Each of the switch means is mounted in what may be termed a switchmodule, providing an integral unit, any number of which may be mountedin the control mechanism to give the necessary control functions for anygiven machine. Each switch module is constructed to be mounted in andremoved from the assembly without disturbing any other parts of themechanism, providing quick and easy replacement in case of malfunction.The aforementioned switch actuating part is coupled to the movablemachine element through a chain drive and gears, thus enabling variationof the travel of the part with respect to a given machine stroke bymerely changing the ratios of the drive parts. As an illustration,assume a control mechanism having an effective travel of 10 inchesutilized to control an injection molding machine having an identical10-inch stroke. The same control mechanism may be used to control amachine having a 40-inch stroke merely by changing the connectingreduction gearing from a l-to-l ratio to one having a 4-to-1 ratio,whereby the control mechanism part now moves only 1 inch for each 4inches of machine stroke. Utilizing the construction shown herein, thebasic structure of the control mechanism may be standard andinterchangeable, and can be adapted to virtually any machine merely byproviding different control-to-machine connections.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial side elevation ofa machine having a reciprocable machine element showing an adjustablecontrol switching mechanism embodying the invention mounted thereon;

FIG. 2 is an enlarged front elevation of an adjustable control switchingmechanism similar to that shown in FIG. 1, with the front cover removedto show details of construction;

FIG. 3 is a section taken along line 33 of FIG. 2 showing details ofconstruction;

FIG. 4 is a section taken along line 4-4 of FIG. 2;

FIGS. 5 and 6 are partial cross-sections taken along lines 55 and 6-6respectively of FIG. 2 showing the structure for coupling the switchingmechanism to a moving machine element;

FIG. 7 is a bottom elevation of one of the switch modules;

FIG. 8 is a side elevation, partly in section, of one of the switchmodules;

FIG. 9 is a cross-section taken along line 9-9 of FIG.

FIG. 10 is a schematic diagram of a modified switch actuating part;

FIG. 11 is a partial top elevation of two switch modules showing meansfor adjusting adjacent switches in unison; and

FIG. 12 is a partial top elevation of the switch actuating table showingmeans for momentarily actuating the switches.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularlyto the drawings, there is shown somewhat schematically in FIG. 1aportion of a machine indicated generally by the numeral having astructural member 22 to which the adjustable control switching mechanism24 embodying the invention is secured. The machine 20 has a pair of tierods or the like 26 upon which a platen 27 reciprocates.

For convenience of description, the machine 20 will be referred toherein as an injection molding machine. However, it is to be understoodthat the mechanism illustrated and described which embodies theinvention is not restricted to use with such a machine, and is in factsuited for use in controlling the operation of virtually any machinehaving an element which moves in a repetitive cycle with each cycle ofmachine operation. Examples of machines the control of which can beaccomplished are: diecasting machines, transfer machines, grindingmachines, and the previously mentioned injection molding machines. It isalso to be noted that while linear reciprocating movement of a machineelement will be referred to throughout the description, machines havingvariousother types of machine element movement may be convenientlycontrolled by a mechanism of the character hereinafter described.

The mechanism 24 embodying the invention may conveniently be enclosed ina rectangular, box-like cabinet 29 including a front panel 28 having atransparent portion 30 so that the controls can be visually observedwithout opening the cabinet. As shown in FIG. 3, the cabinet isconstructed of sheet metal, and includes a bottom wall 32 and integralside walls 34, 35, 36 and 37. The front panel 28 is hinged as at 38 tothe side wall 36 along one side, and has side flanges 46 and 42 whichoverlie the marginal edges of the side walls, the latter being providedwith a U-shaped strip 44 of rubber or the like engaged on their marginaledges against which the panel 28 abuts when closed to keep out dirt anddust. Any convenient holding means may be utilized on the side of thepanel opposite the hinge 38, there being shown a pair of machine screws46 and 48 extending through the panel 28 threadably engageable withsheet metal nuts 50 (FIG. 3) mounted on bracket 52 welded to the sidewall 34. Release of the screws 46 and 48 from their engagement with nuts50 permits the panel 28 to be swung open on hinge 38.

Secured to bottom 32 adjacent the comers thereof are four L-shapedmounting feet 54, 56, 58 and 60 upon which is mounted a pan-like chassis62 having upturned end flanges 64 and 66 (FIG. 3) and side flanges 68and 70 (FIG. 4). The chassis 62 serves as a base for the parts to bedescribed. Extending between and supported in opposite chassis endflanges 64 and 66 are a pair of shafts 72 and 74 (FIGS. 3 and 4) whichare mounted in grommets 76 or the like and are held against axialdisplacement by the legs of the four mounting feet 54, 56, 58 and 60.Atop the shafts 72 and 74 is positioned a cam plate or table 78 havingsecured to its underside four bearing assemblies, two of which are shownon shaft 74 in FIG. 3, the other two similarly positioned on shaft 72.Each bearing assembly includes a bearing block 88 fixed as by welding tothe underside of cam plate 78, and a ball bushing 82. The cam plate 78is thus supported for rectilinear movement back and forth along theshafts 72 and 74.

Mounted on top of the cabinet 29 is a smaller enclosed housing 84 havingtop and side walls, the latter terminating in flanges 86 (FIG. 2)through which screws, bolts or the like (not shown) may extend to securethe housing 84 to the cabinet 29 (FIG. 2). The top wall of cabinet 29 isapertured to accommodate a pair of shafts 88 and 90 in which aresupported for rotation in bearings 92 and 94 mounted on upstandingflange 70 of chassis 62 (FIGS. 2, 5 and 6). Referring to FIG. 5, shaft88 extends through bearing 92 and has an external gear 96 keyed to itsinner end and a sprocket 98 keyed to its outer end. The gear andsprocket are retained on the shaft by an enlarged shaft end portion 100and a nut '102 at its opposite ends. A helical spring 104 encirclesshaft 88 with its inner end fixed to the shaft and its outer end fixedto a stationary part of the assem ly, such as a spring cover member 106.The function of the spring 104 will become apparent as the specificationproceeds.

The remaining shaft 90 (FIG. 6) has both an external gear 108 and asprocket 110 keyed to it, which gear and sprocket are held thereon by aretaining nut 112, and enlarged shaft end portion 113. Housing 84 isprovided with a cutout 114 through which gear 108 projects for matingengagement with a rack 116 fixedly secured to a reciprocating machineelement shown partially at 118. The element 118 may be connected to theplaten 27 shown in FIG. 1. A drive chain 117 shown in FIGS. 2 and 6 isentrained over the sprockets 110 and 98 so that as element 118 andattached rack 116 shift back and forth, gear 108 is rotated by itsengagement with the rack, in turn rotating sprocket 110 and, throughchain 117, sprocket 98. Gear 96 rotates with gear 98, and is in meshwith a second rack 119 which is fixed to the top surface of table 78(see FIGS. 2, 3 and 5). Therefore, as the machine element 1 18reciprocates, a corresponding reciprocating movement is transmitted totable 78 through the system above described and shown in detail in FIGS.5 and 6.

As will be understood by those skiled in the art, the distance traversedby table 78 for a given travel of the machine element 118 and/or platen27 is determined by the sizes of sprockets 98 and l 10, gears 96 and108, and the relationships therebetween. Therefore by varying the ratiobetween the diameters of sprockets 98 and 110, for example, the ratiobetween machine travel and travel of the table 78 may be varied. Asingle control unit 24 having a given maximum table travel may thus beadapted for use with various machines having different stroke lengths.In addition, this adjustability feature permits a comparatively smallunit such as 24 to be uti lized to control a machine having a relativelylong travel.

Referring now particularly to FIGS. 2, 3 and 4, each control unitincludes a plurality of identical switch modules 120, 122, 124 and 126which are supported in cabinet 29 juxtaposed on the path of table 78. Atone end the switch modules are supported on mounting bracket 128 whichis bolted as at 130 to chassis end flange 66 (FIG. 3). Adjacent theopposite end of the chassis 62, there is provided an inverted U-shapedbridge 132 having depending legs 134 and 136 (FIGS. 2 and 4) whichoverlie side chassis flanges 68 and 70 and are secured thereto as bybolts or the like 138. Bridge 132 spans table 78 and supports a box-likeenclosure 140 having integral bottom 142 and end walls 144 and 146, anda separate top 148 which may be secured to inwardly projecting flanges150 of the end walls by screws 152 (FIG. 3). Enclosure 140 may be openat opposite sides as shown. An L-shaped support bracket 154 secured towall 146 as by bolts 156 (FIG. 3) serves to support the opposite end ofthe switch modules 120, 122, 124 and 126, so that they are positioned inspaced relation above table 78.

As shown most clearly in FIGS. 7, 8 and 9, each of the switch modulessuch as 120 comprises a pair of L- shaped members 160 and 162 positionedin allochira] relation with the inner ends of their bases 164 and 166 inclosely spaced parallel relation (FIG. 9). The membes 160 and 162 areheld in position and secured together by blocks 168 and 170 disposedbetween the legs of the members at opposite ends thereof, and fastenedthereto by screws or the like 172 (FIG. 8) to form a unitary switchsupport. The inner surface of the leg of each member 160, 162 has ashallow cutout or slot 174 running its entire length and spaced slightlyabove the respective base 164 or 166. Disposed for slidable movementlongitudinally between members 160 and 162 is a switch carriage 176having a pair of oppositely projecting rails 178 which are positionedwithin the slots 174 to guide the carriage along the support.

A switch 180 of generally standard construction is mounted on thecarriage 176, and includes a projecting actuating button 182 and aflexible arm 184 having a roller 186 at its outer end, whereby upondepression of the roller 186 the switch is actuated by the arm 184depressing the button 182 in conventional fashion. On the side of thecarriage 176 opposite the switch 180, there is a flange 188 whichprojects between the bases 164 and 166 of the support, and engaged uponthe flange is a pointer 190. A graduated scale 192 is adhesively orotherwise secured to the outer face of one of the bases 164 and 166, andthus the position of the carriage and switch along the support may bedirectly read by noting the position of the pointer 190 which overliesthe scale 192.

Mechanism for manually positioning the switch 180 along the module isshown in FIGS. 7 and 8, and comprises a flexible member such as a stoutcord or the like 194 secured to a projection 196 on one end of thecarriage 176. The cord extends around a pulley 198 on block 168, thenceto the opposite end of the module where it is entrained around a shaft200 joumalled for rotation in block 170, and terminating at the otherend of the carriage at a post 202 projecting from an integral carriageblock 204. Pulley 198 rotates on axle 206 which depends from a plate 208swingably supported spaced from block 168 on a post 210. Spring 212connected between plate 208 and a pin 214 urges the plate and pulley ina counterclockwise direction as viewed in FIG. 7, thereby keepingtension on cord 194. Shaft 200 extends outwardly beyond the module 120and has fixed to its projecting end means for manual rotation, such asthe knurled knob shown at 216.

Post 202 has a laterally projecting pin 218 at one end which interfitsin a complementary slot in block 204, and is biased to a positionretaining the pin in the slot by a spring 220. As the cord 194 is fixedto post 202, the post may be depressed against the spring 220 to unseatthe pin 218, and the post then rotated as by a screwdriver or the liketo wind the cord thereon to obtain the desired tautness in the cord 194.With the cord wound about post 200 a couple of times and tightened sothat it is fairly taut, spring 212 will maintain the de sired tension.Rotation of shaft 200 by manipulation of knob 216 shifts the carriage176 and switch along the module 120 to any desired position. However,there is sufficient frictional resistance between the parts so that theswitch 180 will remain in any preselected position even though itsroller 186 is subject to repeated contact with moving table 78 asdescribed more fully herebelow.

In FIGS. 3, 7 and 8, the carriage 176 and switch 180 are shownpositioned at one extremity of their travel along module 120. Referringparticularly to FIG. 3, a relatively rigid hollow tube 222 is shownfixed at one end to the left-hand face of carriage 176 through which theelectrical conductors 224 are led. The tube is provided to support theconductors when the switch is shifted to the right as shown in theseFigs, and is itself supported in an apertured block 226 (FIG. 8). Whenthe switch is shifted to its extreme opposite position (to the right)the tube still projectsinto block 226, thereby preventing dropping orentanglement of the conductors 224 in the mechanism. In the positionshown in FIG. 3, the tube terminates spaced from wall 144 to accommodatea gentle curve of the conductors so they extend back along bottom wall142 to a wire loom 228 in which they are retained. From the wire loom228, the conductors 224 are led through suitable apertures in cover 148and are connected to terminal blocks 230 and 232 secured to the cover.

Also mounted in the cover 148 is a pilot or indicating light 234 foreach switch module, the light being connected in series with arespective switch 180 to give visual indication to the operator wheneverthe switch is actuated. The terminal blocks 230 and 232 are preferablyprotected by a separate cover 236 secured to the upper surface of coverplate 148 as by screws (not shown) extending through the oppositeflanges 238 and 240 of the cover 236. The conductors 224 are led out ofthe cabinet 29 through a suitable fitting 242 (FIG. 2). As shown inFIGS. 2 and 3, a tag or label 244 is secured to cover 236 opposite eachswitch module 120, 122, 124 and 126, upon which there may be printed theidentification of the particular machine function controlled by thatswitch.

As can be seen from an examination of FIGS. 1 and 2, the cabinet 29 maybe made in virtually any size to accommodate the number of switchmodules such as 120 required for the particular machine the functions ofwhich are to be controlled. FIG. 1 shows a device having 12 modules,whilein FIG. 2 there are only four shown. In addition, the length of themodules 121 may be increased or decreased to provide various switchtravels to accommodate machines of different stroke length. Aspreviously stated, the ratio of machine element travel to switch travelmay be varied within a wide range by changing the relative sizes of thesprockets 98 and 110 and/or the gears 96 and 108. Therefore the samebasic device may be utilized to control virtually any machine having amovable element which shifts in a repetitive movement during each cycleof machine operation.

The switch modules are assembled in place by a pair of screws or thelike 246 and 248 which extend through the blocks 168 and 170 at oppositeends of the module (FIG. 8) and through the brackets 128 and 154 (FIG.3) supporting the modules. Access to the screws 246 and 248 is providedby opposed cutouts 250 (See FIG. 2) in the module bases. A positionindicator rod 252 extends across the forward edge of table 78 as shownin FIGS. 2 and 3, and lies spaced above the switch modules 120, 122, 124and 126. The rod 252 is supported at opposite ends in L-brackets 254which are in turn supported on the table by brackets 256. Each bracket254 is fastened to its support 256 by screws or bolts 258 which extendthrough a slot 260 in its base so that the rod 252 may be adjusted withrespect to the table 78. In FIG. 3 it can be seen that rod 252 liesspaced rearwardly from ramp 266 on table 78. By positioning the arrow190 correspondingly with respect to switch roller 186, the rod 252 willlie directly over arrow 190 at the exact instant of switch actuation.The indicator W is limitedly adjustable on flange 188 to provide exactcalibration for each switch.

Once the device is completely assembled, it is mounted on the machine 20to be controlled by fastening the cabinet 29 in a convenient fashion toa stationary machine member 22. The connection with the moving machineelement 27 may be made by fixing a rack 116 to a portion 118 of theelement 27, as shown in FIG. 6, in such fashion that reciprocal movementof the machine element drives pinion 108 through rack 116. Alternately,the gear 108 may be replaced by a reel upon which is wound a flexibletape such as is shown at 262 in FIG. 1, the free end of the tape beingfixed to the movable machine element 27 by means of a clamp or the like264. In the event the tape 262 is used, the spring 104 (FIG. 5) servesas a take-up spring biasing the tape to its retracted or wound-upcondition on the reel which replaces gear 108. If the rack and pinion isused, the spring 104 is utilized in a similar fashion to eliminatebacklash in the gears, sprockets and drive chain illustrated in FIGS. 3,5 and 6.

Once the tape or rack and pinion connection is made, the movement of themachine element 27 rotates memher 108 (FIG. 6), in turn driving piniongear 96 through sprockets 98 and and drive chain 117 (FIG. 6). As pinion96 is in mesh with rack 119 on table 78 (FIGS. 3 and 5), its rotationshifts the table along shafts 72 and 74 (FIG. 3). The leading edge oftable 78 has an inclined ramp portion 266 adjacent its end 268 whichabuts the switch roller 186, and as the roller rides up the ramp, thebutton 182 is depressed by am 184 to actuate the switch. Each switch inthe various modules is actuated in similar fashion as the tablereciprocates along shafts 72 and 74, and as the table 78 traverses anexact cycle of reciprocation with each operating cycle of the machinebeing controlled, the time during the machine cycle at which its variousfunctions are actuated is dependent upon the position of the switches180 along their respective modules 120, 122, 124 and 126, which may beconveniently varied to accomplish any desired sequence and timing of themachine.

In FIG. 10 there is shown an alternate construction which may be used inplace of table 78 and shafts 72 and 74. A switch module with a switchidentical to that above described is shown, in this case mounted foractuation by an articulated table 270 com prising a series of closelyspaced parallel slats 272, 274, 276, etc. mounted on an endless flexiblemember 278 entrained over a pair of rotatable drive members 280 and 282.One of the members 280 or 282 is connected to shaft 88 (FIGS. 3 and 5)in place of pinion 96 and rack 122. The slats 272, etc. travel back andforth as indicated by the double ended arrow in FIG. 10 to actuate theswitches in the same fashion as table 78 in the preceding description.Utilization of table 270 saves space, as it does not extend as far tothe left beyond the module 120 as does table 78. This can be discernedby a comparison of FIGS. 3 and 10.

Assume that it is desired to control the operation of an injectionmolding machine, wherein the cycle of the clamp ram is as follows: rapidforward, slow forward, slow return, rapid return. This is anoversimplification, but will serve for purposes of description.Referring to FIG. 3, these four ram movements may be initiated by theswitches of the four modules 120, 122, 124 and 126, as indicated by thelabels 244i opposite each module. The time during the cycle at whicheach switch is actuated to initiate a respective machine function may bepreset by manually rotating knobs2l6 to position the switches at theproper locations along the modules as indicated by the pointers andscales 192. Accurate positioning is provided by the scales, which may becalibrated to directly read machine position. The machine may then bestarted and run through a few cycles to check its opration, and if anyadjustments are necessary to accomplish exact timing, they may be easilyand conveniently made by rotating the appropriate knobs 216 toreposition the switches, which may be done while the machine is runningwithout any danger to the operator, as all moving parts are shielded,and there is no possibility that the operator can get his hands or partsof his clothing entangled in them.

There are frequent occasions wherein it is necessary to maintain anexact relationship between two or more of the switches used for machinecontrol, while at the same time providing for their adjustment as a unitwith respect to the remaining switches. A simple structure for doingthis shown in FIG. 11, where are shown switch modules 120' and 122, theswitches of which are to be kept in an exact spaced relation, asindicated by the pointers I90 and 190". Three identical gears areprovided, as shown at 290, 292 and 294, with two of them being securedto the shafts under adjusting knobs 216 and 216" respectively, while thethird is mounted for rotation on one of the module members so as to bein mesh with the other two. As can be seen, rotation of either knob 216'or 216" will accomplish identical rotative movement of the other knob,thereby adjusting the two switches the exact same distance along themodules.

Shown in FIG. 12 is a partial top elevation of the table 78 having theinclined ramp portion 266 which contacts the switch rollers to actuatethe switches upon movement of the table. Normally, as can be seen fromFIG. 3, each switch 180 is actuated as its roller 186 is engaged andlifted, and remains actuated until the roller is released upon returnmovement of the table. However, there are certain applications whereinit is desired to actuate a given switch one or more times during eachmachine cycle, but only for a relatively short duration. This momentaryand/or repetitive switch actuation may be accomplished by theutilization of structure such as shown in FIG. 12, wherein a pair ofcenterlines 300 and 302 are shown to schematically represent thelongitudinal axis of a pair of switch modules, for example the twoadjacent modules 120 and 122 in FIG. 2. Mounted atop the upper surfaceof table 78 are a plurality of blocks 304, 306 and 308, each blockhaving tapered opposite end portions 310 and 312 as shown.

Referring to FIG. 3, the appropriate switch modules such as 120 showntherein, are raised above their illustrated position where they will notbe actuated by ramp 266 on the leading edge 268 of the table. Turningback to FIG. 12, the switches will clear ramp 266 as the table passesthe switch rollers, but the blocks 304, 306 will contact the switchroller of the switch on line 300, actuating the switch twice for a shortduration during each cycle, while block 308 will actuate the switch online 302 once momentarily. The blocks may be made in different lengthsto actuate the switches for any desired period during the cycle, and anynumber of blocks may be used for repeated switch actuation during asingle cycle. Furthermore, with two switches wired in series actuationof both switches is required to initiate machine function, and time andduration may be controlled even further by this expedient.

What is claimed is:

1. Mechanism for controlling the operation of a machine or the likehaving a cyclically movable element, comprising, in combination: agenerally rectangular enclosure having a rear wall with means forsecurement to said machine, upstanding side walls and a front wallhingedly connected to one of said side walls for swingable movement toexpose the interior of the enclosure; support means mounted on said rearwall; a plurality of elongate switch modules removably mounted on saidsupport means in closely spaced parallel relation, each module includinga support generally U-shaped in cross section with the bight of theU-shape facing said front wall and an electric switch means supportedbetween the legs of the U-shape for selective positioning therealong andhaving a switch actuating arm projecting be yond the free ends of thelegs; a reciprocable part mounted on said support means rearwardly ofsaid modules for movement in a path parallel to the longitudinal axes ofsaid modules and having a switch actuating portion adapted to engagesaid switch arms to actuate each switch means during reciprocation ofthe part; means operatively connected to said part and to said movablemachine element for translating cyclical element movement intocorresponding linear reciprocal part movement; and means connected toeach of said switch means for selectively positioning each switch meansalong its respective support and having a manually manipulatable portionprojecting forwardly of said module.

2. Mechanism as defined in claim 1 characterized in that said means fortranslating element movement into linear reciprocal part movementcomprises a first rotatable member connected to said machine element forrotation in response to element movement, a second rotatable memberengaging said part to impart linear movement thereto upon rotation ofsaid second member, and drive means interposed between said first andsecond rotatable members for transmitting movement therebetween.

3. Mechanism as defined in claim 1 characterized in that saidreciprocable part comprises a flat table member having a leading edgedefining said switch actuating portion extending perpendicular to thelongitudinal switch module axes substantially completely across all ofsaid modules.

4. Mechanism as defined in claim 3 characterized in that said tablemember defines at least one switch actuating block mounted on the tableand projecting above the flat surface thereof in axial alignment with atleast one of said switch modules, with said one switch module beingmounted with its switch arm spaced above the table out of the path ofsaid leading edge for actuation by said block.

5. Mechanism as defined in claim 1 characterized in that each of saidswitch modules is a unitary structure including an elongate support,switch means and switch positioning means independently disconnectablymounted on said support.

6. Mechanism as defined in claim 1 characterized in that each switchmeans includes electrical conductor means extending therefrom forconnection to said machine, and an indicator light is mounted in saidenclosure electrically connected in series with each said switch means.

7. Mechanism as defined in claim 3 characterized in that each switchmeans includes position indicator means indicating the position of theswitch means along its respective module, and said, table memberincludes visual position indicator means: bridging all of said switchmodules parallel to said table leading edge for indicating the positionof said edge along said modules.

8. Mechanism as defined in claim 1 characterized in that at least two ofsaid means for positioning each switch means along its support areinterconnected for conjoint movement to thereby position two switchmeans equal distances along their supports upon manipulation of one ofsaid two positioning means.

9. In mechanism for controlling machine operation including a pluralityof switch means, a switch module comprising: an elongate support havinga pair of side walls defining spaced apart parallel guideways, a switchcarriage having a pair of projections in cooperating engagement withsaid guideways for movement of said carriage along the support, switchmeans on said carriage positioned for actuation by means external of themodule, means connected to the carriage for shifting the carriage andswitch means in opposite directions along said support and includingmeans for retaining the carriage in any preselected position therealong,and conductor means connected to said switch means and extendingtherefrom for connection to said machine.

10. A switch module as defined in claim 9 characterized in that saidsupport comprises a pair of elongate, allochiral, L-shaped portionspositioned in spaced, parallel relation with co-planar bases projectingtoward each-other, said switch carriage disposed between the legs ofsaid L-shaped portions for guided movement therebetween, and said switchmeans mounted on said carriage intermediate the free ends of said legsfor actuation by means external of the module.

11. A switch module as defined in claim 9 characterized in that saidconductor means includes a plurality of flexible electrical conductorsand a protective, relatively rigid tubular member enclosing saidconductors, said tubular member connected to said carriage at one endand being of sufficient length to protect the conductors throughout thelength of said support in all positions of said carriage therealong.

12. A switch module as defined in claim 10 characterized in that saidsupport is provided with a scale on an exposed face thereof and anindicator is fixed on said carriage having a portion overlying saidscale for indicating the position of said switch means along thesupport.

13. A switch module as defined in claim 12 characterized in that saidscale is positioned on an outwardly facing surface of one of said legsof said L-shaped portions, and said indicator projects-between the legfree ends and defines a pointer overlying said scale.

14. A switch module as defined in claim 9 characterized in that saidswitch means comprises a mechanically actuated switch having an externalactuating arm projecting beyond said support side walls for switchactuating engagement by means external of the module.

15. A switch module as defined in claim 9 characterized in that saidmeans for shifting the carriage comprises a flexible elongate cordconnected at opposite ends to said carriage, a shaft joumalled forrotation in said support, and manually manipulatable means on the shaftfor rotating the same, said cord being wound about the shaftintermediate said ends.

1. Mechanism for controlling the operation of a machine or the likehaving a cyclically movable element, comprising, in combination: agenerally rectangular enclosure having a rear wall with means forsecurement to said machine, upstanding side walls and a front wallhingedly connected to one of said side walls for swingable movement toexpose the interior of the enclosure; support means mounted on said rearwall; a plurality of elongate switch modules removably mounted on saidsupport means in closely spaced parallel relation, each module includinga support generally U-shaped in cross section with the bight of theU-shape facing said front wall and an electric switch means supportedbetween the legs of the U-shape for selective positioning therealong andhaving a switch actuating arm projecting beyond the free ends of thelegs; a reciprocable part mounted on said support means rearwardly ofsaid modules for movement in a path parallel to the longitudinal axes ofsaid modules and having a switch actuating portion adapted to engagesaid switch arms to actuate each switch means during reciprocation ofthe part; means operatively connected to said part and to said movablemachine element for translating cyclical element movement intocorresponding linear reciprocal part movement; and means connected toeach of said switch means for selectively positioning each switch meansalong its respective support and having a manually manipulatable portionprojecting forwardly of said module.
 2. Mechanism as defined in claim 1characterized in that said means for translating element movement intolinear reciprocal part movement comprises a first rotatable memberconnected to said machine element for rotation in response to elementmovement, a second rotatable member engaging said part to impart linearmovement thereto upon rotation of said second member, and drive meansinterposed between said first and second rotatable members fortransmitting movement therebetween.
 3. Mechanism as defined in claim 1characterized in that said reciprocable part comprises a flat tablemember having a leading edge defining said switch actuating portionextending perpendicular to the longitudinal switch module axessubstantially completely across all of said modules.
 4. Mechanism asdefined in claim 3 characterized in that said table member defines atleast one switch actuating block mounted on the table and projectingabove the flat surface thereof in axial alignment with at least one ofsaid switch modules, with said one switch module being mounted with itsswitch arm spaced above the table out of the path of said leading edgefor actuation by said block.
 5. Mechanism as defined in claim 1characterized in that each of said switch modules is a unitary structureincluding an elongate support, switch means and switch positioning meansindependently disconnectably mounted on said support.
 6. Mechanism asdefined in claim 1 characterized in that each switch means includeselectrical conductor means extending therefrom for connection to saidmachine, and an indicator light is mounted in said enclosureelectrically connected in series with each said switch means. 7.Mechanism as defined in claim 3 characterized in that each switch meansincludes position indicator means indicating the position of the switchmeans along its respective module, and said table member includes visualposition indicator means bridging all of said switch modules parallel tosaid table leading edge for indicating the position of said edge alongsaid modules.
 8. Mechanism as defined in claim 1 characterized in thatat least two of said means for positioning each switch means along itssupport are interconnected for conjoint movement to thereby position twoswitch means equal distances along their supports upon manipulation ofone of said two positioning means.
 9. In mechanism for controllingmachine operation including a plurality of switch means, a switch modulecomprising: an elongate support having a pair of side walls definingspaced apart parallel guideways, a switch carriage having a pair ofprojections in cooperating engagement with said guideways for movementof said carriage along the support, switch means on said carriagepositioned for actuation by means external of the module, meansconnected to the carriage for shifting the carriage and switch means inopposite directions along said support and including means for retainingthe carriage in any preselected position therealong, and conductor meansconnected to said switch means and extending therefrom for connection tosaid machine.
 10. A switch module as defined in claim 9 characterized inthat said support comprises a pair of elongate, allochiral, L-shapedportions positioned in spaced, parallel relation with co-planar basesprojecting toward each other, said switch carriage disposed between thelegs of said L-shaped portions for guided movement therebetween, andsaid switch means mounted on said carriage intermediate the free ends ofsaid legs for actuation by means external of the module.
 11. A switchmodule as defined in claim 9 characterized in that said conductor meansincludes a plurality of flexible electrical conductors and a protective,relatively rigid tubular member enclosing said conductors, said tubularmember connected to said carriage at one end and being of sufficientlength to protect the conductors throughout the length of said supportin all positions of said carriage therealong.
 12. A switch module asdefined in claim 10 characterized in that said support is provided witha scale on an exposed face thereof and an indicator is fixed on saidcarriage having a portion overlying said scale for indicating theposition of said switch means along the support.
 13. A switch module asdefined in claim 12 characterized in that said scale is positioned on anoutwardly facing surface of one of said legs of said L-shaped portions,and said indicator projects between the leg free ends and defines apointer overlying said scale.
 14. A switch module as defined in claim 9characterized in that said switch means comprises a mechanicallyactuated switch having an external actuating arm projecting beyond saidsupport side walls for switch actuating engagement by means external ofthe module.
 15. A switch module as defined in claim 9 characterized inthat said means for shifting the carriage comprises a flexible elongatecord connected at opposite ends to said carriage, a shaft journalled forrotation in said support, and manually manipulatable means on the shaftfor rotating the same, said cord being wound about the shaftintermediate said ends.